<%#
 Copyright 2013-2020 the original author or authors from the JHipster project.

 This file is part of the JHipster project, see https://www.jhipster.tech/
 for more information.

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-%>
package <%= packageName %>.security.jwt;

import java.nio.charset.StandardCharsets;
import java.security.Key;
import java.util.*;
import java.util.stream.Collectors;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.User;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

import io.github.jhipster.config.JHipsterProperties;
import io.jsonwebtoken.*;
import io.jsonwebtoken.io.Decoders;
<%_ if (reactive) { _%>
import io.jsonwebtoken.jackson.io.JacksonSerializer;
<%_ } _%>
import io.jsonwebtoken.security.Keys;

@Component
public class TokenProvider {

    private final Logger log = LoggerFactory.getLogger(TokenProvider.class);

    private static final String AUTHORITIES_KEY = "auth";

    private final Key key;

    private final JwtParser jwtParser;

    private final long tokenValidityInMilliseconds;

    private final long tokenValidityInMillisecondsForRememberMe;

    public TokenProvider(JHipsterProperties jHipsterProperties) {
        byte[] keyBytes;
        String secret = jHipsterProperties.getSecurity().getAuthentication().getJwt().getSecret();
        if (!StringUtils.isEmpty(secret)) {
            log.warn("Warning: the JWT key used is not Base64-encoded. " +
                "We recommend using the `jhipster.security.authentication.jwt.base64-secret` key for optimum security.");
            keyBytes = secret.getBytes(StandardCharsets.UTF_8);
        } else {
            log.debug("Using a Base64-encoded JWT secret key");
            keyBytes = Decoders.BASE64.decode(jHipsterProperties.getSecurity().getAuthentication().getJwt().getBase64Secret());
        }
        key = Keys.hmacShaKeyFor(keyBytes);
        jwtParser = Jwts.parserBuilder().setSigningKey(key).build();
        this.tokenValidityInMilliseconds =
            1000 * jHipsterProperties.getSecurity().getAuthentication().getJwt().getTokenValidityInSeconds();
        this.tokenValidityInMillisecondsForRememberMe =
            1000 * jHipsterProperties.getSecurity().getAuthentication().getJwt()
                .getTokenValidityInSecondsForRememberMe();
    }

    public String createToken(Authentication authentication, boolean rememberMe) {
        String authorities = authentication.getAuthorities().stream()
            .map(GrantedAuthority::getAuthority)
            .collect(Collectors.joining(","));

        long now = (new Date()).getTime();
        Date validity;
        if (rememberMe) {
            validity = new Date(now + this.tokenValidityInMillisecondsForRememberMe);
        } else {
            validity = new Date(now + this.tokenValidityInMilliseconds);
        }

        return Jwts.builder()
            .setSubject(authentication.getName())
            .claim(AUTHORITIES_KEY, authorities)
            .signWith(key, SignatureAlgorithm.HS512)
            .setExpiration(validity)
            <%_ if (reactive) { _%>
            .serializeToJsonWith(new JacksonSerializer())
            <%_ } _%>
            .compact();
    }

    public Authentication getAuthentication(String token) {
        Claims claims = jwtParser.parseClaimsJws(token).getBody();

        Collection<? extends GrantedAuthority> authorities =
            Arrays.stream(claims.get(AUTHORITIES_KEY).toString().split(","))
                .map(SimpleGrantedAuthority::new)
                .collect(Collectors.toList());

        User principal = new User(claims.getSubject(), "", authorities);

        return new UsernamePasswordAuthenticationToken(principal, token, authorities);
    }

    public boolean validateToken(String authToken) {
        try {
            jwtParser.parseClaimsJws(authToken);
            return true;
        } catch (JwtException | IllegalArgumentException e) {
            log.info("Invalid JWT token.");
            log.trace("Invalid JWT token trace.", e);
        }
        return false;
    }
}
